From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0097.outbound.protection.outlook.com ([104.47.42.97]:1354 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752821AbeBCSD4 (ORCPT ); Sat, 3 Feb 2018 13:03:56 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Nikolay Borisov , David Sterba , Sasha Levin Subject: [PATCH AUTOSEL for 4.14 070/110] btrfs: Fix flush bio leak Date: Sat, 3 Feb 2018 18:01:15 +0000 Message-ID: <20180203180015.29073-70-alexander.levin@microsoft.com> References: <20180203180015.29073-1-alexander.levin@microsoft.com> In-Reply-To: <20180203180015.29073-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Nikolay Borisov [ Upstream commit beed9263f4000c48a5c48912f26576f6fa091181 ] Commit e0ae99941423 ("btrfs: preallocate device flush bio") reworked the way the flush bio is allocated and used. Concretely it allocates the bio in __alloc_device and then re-uses it multiple times with a very simple endio routine that just calls complete() without consuming a reference. Allocated bios by default come with a ref count of 1, which is then consumed by the endio routine (or not, in which case they should be bio_put by the caller). The way the impleementation works now is that the flush bio has a refcount of 2 and we only ever bio_put it once, leaving it to hang indefinitely. Fix this by removing the extra bio_get in __alloc_device. Fixes: e0ae99941423 ("btrfs: preallocate device flush bio") Signed-off-by: Nikolay Borisov Reviewed-by: Liu Bo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/volumes.c | 1 - 1 file changed, 1 deletion(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 4006b2a1233d..bc534fafacf9 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -236,7 +236,6 @@ static struct btrfs_device *__alloc_device(void) kfree(dev); return ERR_PTR(-ENOMEM); } - bio_get(dev->flush_bio); =20 INIT_LIST_HEAD(&dev->dev_list); INIT_LIST_HEAD(&dev->dev_alloc_list); --=20 2.11.0